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PubMed2000

Antimicrobial resistance in Streptococcus pyogenes isolates in Berlin.

A total of 212 clinical Streptococcus pyogenes isolates were tested for susceptibility to various antibiotics by agar dilution. The overall frequency of erythromycin resistance was 12.7%, being higher in isolates from children (18.9%) than in those from adult patients (10.7%). Similar results were found for clarithromycin, while 2.8% of the isolates were resistant to ciprofloxacin. All strains were susceptible to penicillin and cefotaxime. Of the erythromycin-resistant isolates subjected to the double-disc diffusion test for erythromycin and clindamycin, 35% expressed constitutive and 55% inducible resistance to clindamycin. Ten per cent were susceptible to clindamycin (M-phenotype). Thus, a high rate of macrolide resistance in S. pyogenes has emerged in Berlin.

Adolescent↗

PubMed1997

Localization by site-directed mutagenesis of the site in human complement factor H that binds to Streptococcus pyogenes M protein.

M-protein receptors located on Streptococcus pyogenes cells are known to bind human plasma protein factor H. Human factor H is composed of 20 short consensus repeat (SCR) domains containing approximately 60 amino acids each. Factor H controls the activation of the alternative pathway of complement in plasma. We have scanned the entire human factor H molecule by site-directed deletion mutagenesis, expressed the recombinant proteins in insect cells using the baculovirus system, and measured the binding of different purified mutant proteins to three strains of S. pyogenes. These studies have revealed that recombinant factor H lacking SCR domains 6 to 10 does not bind to wild-type M+ S. pyogenes JRS4. Experiments performed with S. pyogenes JRS251, in which both C-repeat domains of M protein were deleted, demonstrated that all of the factor H mutant proteins bound weakly to these cells except those lacking the SCR region from domains 6 to 10. Neither human factor H nor any of the recombinant proteins bound to the M- strain JRS145. Our results indicate that the only binding site on human factor H that interacts with streptococcus M protein is located in SCR domains 6 to 10 of factor H and that regions of M protein outside the C-repeat domains are involved in binding factor H.

Animals↗

PubMedDate not supplied

[Mouth colonization by Streptococcus pyogenes in patients with impetigo].

The faucial carrying of Streptococcus pyogenes in patients presenting impetigo was determined as a risk factor for non-suppurative complications (acute glomerulonephritis). The fauces cultures of these patients revealed a S. pyogenes colonization of 65% and all the isolates were penicillin-sensitive. It was concluded that the high percent of faucial colonization made a systemic antimicrobial treatment necessary.

Adolescent↗

PubMed2002

EndoS and SpeB from Streptococcus pyogenes inhibit immunoglobulin-mediated opsonophagocytosis.

The human pathogen Streptococcus pyogenes primarily infects the upper respiratory tract and skin, but occasionally it disseminates and causes severe invasive disease with high mortality. This study revealed that the activity of extracellular EndoS, which hydrolyzes the functionally important N-linked oligosaccharides on opsonizing immunoglobulin G (IgG), contributes to increased survival of S. pyogenes in human blood ex vivo. The inability to kill the bacteria is due to reduced binding of IgG to Fc receptors and impaired classical pathway-mediated activation of complement. In addition, the activity of extracellular SpeB, which cleaves IgG into Fc and Fab fragments, also increases bacterial survival. This suggests that S. pyogenes expresses two enzymes, EndoS and SpeB, which modulate IgG by different mechanisms in order to evade the adaptive immune system.

Bacterial Proteins↗

PubMed1994

M-like, immunoglobulin-binding protein of Streptococcus pyogenes type M15.

An M-like protein from Streptococcus pyogenes type M15 strain EF1949 (EMML15) was cloned in Escherichia coli and sequenced. Recombinant EMML15 protein revealed a unique binding pattern for human IgG subclasses not described previously. Comparative analysis of the EMML15 amino acid sequence with those of other M-like proteins of opacity factor positive (OF+) serotypes and protein H, and IgG receptor from OF- serotype M1, showed that IgG-binding proteins with common binding of IgG3 were closely related and distinct from streptococcal IgG receptors not binding IgG3. Thus, the Ig-binding proteins from S. pyogenes were subdivided into two main categories according to binding pattern, protein structure, and gene location.

Amino Acid Sequence↗

PubMed1975

Plasmid-determined resistance to erythromycin: comparison of strains of streptococcus faecalis and streptococcus pyogenes with regard to plasmid hmology and resistance inducibility.

Streptococcus faecalis strains DS-5 and Streptococcus pyogenes strain AC-1 both have a 17 million dalton plasmid that determines resistance to erythromycin, lincomycin, and vernamycin B(alpha). The results of deoxyribonucleic acid-deoxyribonucleic acid hybridization experiments indicate that the two plasmids are about 95% homologous. It was also shown that erythromycin resistance is inducible in AC-1 and constitutive in DS-5.

Drug Resistance, Microbial↗

PubMed1981

[Studies of the heterogeneity of streptokinases; IV. Evidence for isostreptokinases in Streptococcus pyogenes type 1 (author's transl)].

Two strains of Streptococcus pyogenes, originating from the same Griffith strain SF 130/13 but different in M protein synthesis, produce two isostreptokinases. The molecular weights of both isostreptokinases are the same (about 50 000 daltons) as well as the specific activities (38 000 and 43 000 U/mg, resp.). The activity values are influenced by an incomplete removal of ampholytes. The isoelectric points were determined as pI 6.3, and 6.5, resp. The presence of isostreptokinases was concluded by (1) the absence of proteolytic activities in the culture filtrate, (2) the same molecular weights, (3) the same specific activities, (4) the constant quantitative relation of about 1:2.5 between both isostreptokinases after refocusing, (5) a lack of cystein- or cystin residues in the molecule, (6) the appearance of both isostreptokinases in untreated culture filtrates, (7) the separability by disc electrophoresis, and (8) the lack of such double bands in streptokinases of other streptococci. Isoelectric focusing of streptokinase produced by a type 3 strain of S. pyogenes was followed by the appearance of four bands with streptokinase activity. It is unlikely that these four bands represent isostreptokinases. Both streptokinases (type 1 and type 3 streptococci) differ from streptokinases of other types by their relatively high content of tryptophane (table 1) and the high isoelectric points (6.5 to 6.0; streptokinases of other types and groups show pI's between 5.05 to 5.65 (6).

Isoelectric Point↗

PubMed1990

Streptococcus pyogenes: an outbreak on a burns unit.

An outbreak of infection with Streptococcus pyogenes (Group A beta-haemolytic streptococcus) on a burns unit described. The control measures taken are outlined, and the route of spread of infection is discussed along with possible preventative measures.

Burn Units↗

PubMed1979

The role of M protein in phagocytosis. I. Activity of some enzymes in phagocytic cells during infection with Streptococcus pyogenes in vivo.

The phagocytosis of two type 12 Streptococcus pyogenes strains differing in M protein presence was investigated in vivo. The rate of phagocytosis and the streptococcal viability in phagocytic cells and outside of them was studied simultanously with estimation of enzymatic activity in phagocytic cells. It was observed that M positive strain was phagocytized at lower rate and also exhibited longer viability. Decrease of lactic dehydrogenase and ATP-ase activity in phagocytes of rabbits infected with M+ strain was also detected. These results suggest that M protein disturbs phagocytosis by inhibiting their main metabolic pathway of glycolysis.

Acid Phosphatase↗

PubMed2005

[Streptococcus pyogenes and Mycoplasma pneumoniae: pulmonary coinfection or serologic artefact?].

INTRODUCTION: How should Mycoplasma pneumoniae seroconversion be interpreted in a patient with community-acquired Streptococcus pyogenes pneumonia? CASE: A 21-year-old man with cerebral palsy was hospitalized with acute pneumonia and fever. The bronchoalveolar lavage fluid contained Streptococcus pyogenes, and serological testing for Mycoplasma pneumoniae was positive. At 4 weeks, measurements of anti-M. pneumoniae and antistreptolysin O antibodies were positive. DISCUSSION: Two hypotheses should be considered: the patient has either a coinfection of S. pyogenes and M. pneumoniae or a nonspecific antibody response during a severe S. pyogenes infection.

Adult↗

PubMed1987

Cell growth-inhibitory action of SAGP, an antitumor glycoprotein from Streptococcus pyogenes (Su strain).

An antitumor acidic glycoprotein (SAGP) from Streptococcus pyogenes (Su strain) inhibited the growth of BALB/3T3 cells in culture in a dose-dependent manner (0.03-10.0 micrograms/ml). This effect of SAGP was abolished by washing the cells, suggesting that SAGP weakly binds to the cell membrane. The ability of the cells to form colonies was unaffected by three days exposure to SAGP. Cell cycle analysis by flow cytometry revealed an accumulation of SAGP-treated cells in the S-phase. SAGP (3 micrograms/ml) reduced the incorporation of 3H-thymidine into the cells to approximately half of the control level. These results suggest that SAGP inhibits the growth of target cells by acting on their surface membrane and decreasing the rate of DNA synthesis.

Bacterial Proteins↗

PubMed2004

Hyaluronan release from Streptococcus pyogenes: export by an ABC transporter.

Capsular hyaluronan of Streptococcus pyogenes is synthesized at the protoplast membrane. It is widely assumed that hyaluronan is exported by the synthase itself and that no additional protein is required for transfer through plasma membranes. However, we produced an insertional mutation that reduced the mucoid phenotype, hyaluronan production, and capsule formation. Nucleotide sequence analysis of the insertion site identified a gene coding for a protein with an ATP-binding cassette (ABC) that belonged to an ABC transporter system and was located next to the hyaluronan synthesis genes. The mucoid phenotype was reconstituted by complementation with DNA encoding the ABC transporter system. These results indicated that an ABC transporter was required for efficient capsule production.

ATP-Binding Cassette Transporters↗

PubMed1996

Atypical Streptococcus pyogenes from an ear discharge.

An atypical variant of Streptococcus pyogenes was isolated from a discharge from a child's ear. Although this variant streptococcus grew aerobically on chocolate agar, the isolate would not grow on blood agar, the medium used to screen for S. pyogenes, unless it was incubated anaerobically or incubated in air with cocarboxylase.

Child, Preschool↗

PubMed1989

Identification of a divergent M protein gene and an M protein-related gene family in Streptococcus pyogenes serotype 49.

The antigenically variant M protein of Streptococcus pyogenes enhances virulence by promoting resistance to phagocytosis. The serum opacity factor (OF), produced by a subset of M serotypes, is also antigenically variant, and its antigenic variability exactly parallels that of M protein. OF-positive and OF-negative streptococci are also phenotypically distinguishable by a number of other criteria. In order to study the differences between OF-positive and OF-negative streptococci, we cloned and sequenced the type 49 M protein gene (emm49), the first to be cloned from an OF-positive strain. This gene showed evolutionary divergence from the OF-negative M protein genes studied previously. Furthermore, emm49 was part of a gene family, in contrast to the single-copy nature of previously characterized M protein genes.

Amino Acid Sequence↗

PubMed1996

Properties of IgG-binding proteins expressed by Streptococcus pyogenes isolates are predictive of invasive potential.

Recent clinical Streptococcus pyogenes isolates of the M1 serotype can be grouped according to the IgG-binding properties of their M proteins. One group expressed an IgG-binding M1 protein reactive with human IgG1, IgG2, IgG3, and IgG4 (type IIo); the other expressed a protein with predominant reactivity with human IgG3 alone (type IIb). Both IgG-binding protein phenotypes were equally resistant to phagocytosis in human blood; however, when they were injected into a skin air sac on outbred CD1 mice, all mice injected with M1 isolates of the type IIo phenotype were dead within 70 h, while only 40% of those injected with M1 isolates of the type IIb phenotype died within the same period. Bacteria recovered from the spleens of animals that died after injection with type IIb phenotype isolates demonstrated a change in their IgG-binding profile and were indistinguishable, in vitro or in vivo, from isolates displaying the type IIo phenotype.

Animals↗

PubMed1992

The characterization of two new low molecular weight proteins (LMPs) from Streptococcus pyogenes.

Two novel extracellular mitogenic substances were isolated from Streptococcus pyogenes strain NY-5 and characterized. The purification steps involved an initial enrichment of the proteins from culture supernatant by silica gel adsorption, followed by ion exchange chromatography and gel filtration. The purified materials were homogeneous in SDS-PAGE, showed estimated molecular weights of 12 kD and isoelectric points of 4.7 and 4.3, respectively. Both proteins (LMP-12k-4.3pI and LMP-12k-4.7pI) demonstrated lymphocyte transformation activity at a concentration of 0.1 microgram/ml. The LMP-12k-4.7pI showed a 69.2% homology of the amino acid sequence with that of a phosphocarrier protein of Staphylococcus aureus and with a total identity in the active centre. The same protein was also isolated from streptococcal group C strain H46A with an N-terminal amino acid sequence being identical. The LMP-12k-4.7pI demonstrated biochemical properties identical with those of the earlier described streptococcal pyrogenic exotoxin type D. The LMP-12k-4.3pI did not show such a clear relation to other functional proteins.

Amino Acid Sequence↗

PubMed2005

Identification of residues responsible for the defective virulence gene regulator Mga produced by a natural mutant of Streptococcus pyogenes.

Mga is a transcriptional regulator in the pathogen Streptococcus pyogenes that positively activates several important virulence genes involved in colonization and immune evasion in the human host. A naturally occurring mutant of Mga that is defective in its ability to activate transcription has been identified in the serotype M50 strain B514-Sm. Sequence alignment of the defective M50 Mga with the fully functional Mga from serotypes M4 and M49 revealed only three amino acid changes that might result in a defective protein. Electrophoretic mobility shift assays using purified M50 and M4 maltose binding protein-Mga found that both exhibited DNA-binding activity towards regulated promoters. Thus, the significance of each residue for the functionality of M50 Mga was explored through introduction of "gain-of-function" mutations based on M4 Mga. Transcriptional studies of the mutant alleles under both constitutive (PrpsL) and autoactivated (Pmga4) promoters illustrated that an arginine-to-methionine change at position 461 of M50 Mga protein fully restored activation of downstream genes. Western blot analyses of steady-state Mga levels suggest that the M461 residue may play a role in overall conformation and protein stability of Mga. However, despite the conservation of the M461 protein among all other Mga proteins, it does not appear to be necessary for activity in a divergent M6 Mga. These studies highlight the potential differences that exist between divergent Mga proteins in this important human pathogen.

Bacterial Proteins↗

PubMed1992

DNA restriction fragment length polymorphism differentiates recurrence from relapse in treatment failures of Streptococcus pyogenes pharyngitis.

In the evaluation of treatment failure in Streptococcus pyogenes pharyngitis it is necessary to distinguish between persistence of the original streptococcus and acquisition of a new strain. We used the analysis of restriction fragment length polymorphism (RFLP) of total DNA and of ribosomal DNA (rDNA) regions (ribotypes) as epidemiological tools to compare 43 pre- and post-treatment S. pyogenes strains obtained from 20 patients. In 16 cases pre- and post-treatment strains gave indistinguishable RFLP patterns of total DNA, strongly suggesting relapse with the same strain. However, in four cases different patterns were obtained for the pre- and post-treatment isolates, indicating recurrence due to the acquisition of a new strain. Ribotyping did not improve discrimination among strains. Thus, analysis of DNA RFLP is a promising method for distinguishing recurrence from relapse in failures of pharyngitis treatment.

DNA, Bacterial↗